1. Field of the Invention
The present invention relates to stitching, or stapling, collated signatures. Particularly, the present invention relates to a stitching head used for stapling collated signatures together.
2. Description of the Prior Art
Machines which form staples from wire and drive the staples into collated signatures are known. These known machines are typically used for binding books, pamphlets, magazines and the like.
Two signature collating machines which include a stitching head are disclosed in U.S. Pat. Nos. 4,196,835 and 4,236,706. The stitching heads are disposed above the path of a saddle conveyor which moves collated signatures. Each stitching head moves along a portion of the path in synchronization with the collated signatures. A clincher is disposed below the moving collated signatures. The stitching heads bend a short piece of wire to form a staple and drive the staple through the collated signatures as the signatures move. The clincher folds the ends of the staple to finish the stitching operation.
The stitching head of U.S. Pat. No. 4,196,835 includes a drive shaft which carries cams. Upon rotation of the drive shaft, the cams operate the stitching mechanism and clincher through linkage assemblies. The signature collating machines of the aforementioned patents perform satisfactorily and accomplish high speed binding. However, as with any system, there is a continuing need to make certain improvements.